Use TDD for bits that have very limited scope and function. For instance, an order book class or similar. Otherwise code first, test bugs if needed. For smaller projects (that aren't critical espc.) overtesting can kill your momentum and motivation, which is an often overlooked resource.
It suggests some sort of cabal wanting them produced, and moving in the shadows to make it happen. Of course this is very much in line with the stories themselves, but that doesn't help at all.
Personally, I'd love to see e.g. The Culture novels be made into a show, or series of films. There was talk of making a Consider Phlebas TV show some time back, though I don't think it went anywhere. Heinlein's "The Moon Is A Harsh Mistress" could also do well as a stand alone movie, though possibly with Heinlein you would need to tone down the polygamy themes.
As to why PKD became such a cinematic mainstay I can't quite tell. I would think part of it would be to do with the fact that many of his stories were less about the "lasers and spaceships" part of SciFi, and more about the moral and human aspect, meaning costs could be saved on big budget set pieces ala Star Wars.
I find structures like conways game of life, or slime mold or sand dunes to be fascinating for this reason. That from unit simplicity can emerge aggregate complexity, imitating facets of nature.
In my case any design be it software, a drawing, or project or something else needs to start with a couple of rough diagrams and notes on paper. I have tried numerous times to do this electronically and it has failed every single time.
Not sure why, but there seems to be something about the fluidity of writing that allows you to get thoughts and expressions down quickly in a way that boxes and flowcharts just don't facilitate.
Most of the time I view these notes for a few days while I work or write proper documentation and after that they are left behind. I have several stacks of various notebooks lying around filled with stuff like this.